warning C4700: uninitialized local variable 'BottlesLeft' used

Hi there pleasse help. I get the warning C4700: uninitialized local variable 'BottlesLeft' used. Here is what the CalcNrCases is supposed to do: A value-returning function called CalcNrCases( BottleType, NrBottles, BottlesLeft ) that will calculate and return the number of full cases (NrCases) as an integer. It will also calculate and pass back how many bottles are left that will not be paid for (BottlesLeft) as an integer. The type of the bottle determines how many fit into a case:
• ‘S’ or ‘s’ = 375ml bottles, 10 per case
• ‘M’ or ‘m’ = 500ml bottles, 8 per case
• ‘L’ or ‘l’ = 750ml bottles, 6 per case
Also I am not sure if my formulas are correct.